std 7 science ch 10 swadhyay pothi ,dhoran 7 vigyan swadhyay pothi , dhoran 7 swadhyay pothi vigyan

Class 10 Science | Chapter 7 Control and Coordination | Important Questions and Quick Revision

Glycine [NH_(2)CH_(2)COOH) is basic and acidic due to presence of -NH_(2) and -COOH group. It acquires a H^(o+) to form overset(o+)NH_(3)COOH , which is a diprotic acid with K_(1) = 4.5 5 10^(-3) and K_(2) = 1.7 xx 10^(-10) . In a 0.01M solution of neutral glycine, a. What is the pH and b. What percent of the glycine is in the cationic form at equilibrium?

A solution capable of maintaining its pH relatively constatn, when either excess acid or excess base is added, is said to be buffered While it is not usually considered a buffered solution, a concentrated solution (10^(-2) M and higher) of a strong acid or stong base is buffered against large changes in pH when acids or bases are added. Buffered solutions are usually those containing a wealk acid and a salt of that weak acid or a weak base and the salt of that weak base. For example a solution containing HAc and NaAC resists large change in pH when acid or alkali is added. For a buffer solution Buiffer capacity is defined as the number of moles of a strong acid or a strong base that causes 1 of the buffer to undergo a 1 unit change in pH. Buffer capacity is maximum when the molar ratio of the two components is unity and the buffer solution is considerred good. Which is the best buffer? CH_(3)COOH(pK_(a)=4.7),CH_(3)COONa(M=82),CH_(3)COOH(M=60)

Many of us believe that science is something modern ...(1)... the truth is that ...(2)... has been using science for ...(3)... very long time. However, it has ...(4)... a greater effect on human lives in the last 25 ...(5)... 30 years than in the hundreds of years ...(6)... the invention of the plough. The ...(7)... gifts of science have modern life ...(8)... and comfortable. But science has ...(9)... the same time created new problems. one of these which may become ...(10)... in the years to come, is ...(11)... of "jet-lag". With the coming of modern jets. flying at more than 900 km/hr, the world ...(12)... very small indeed. Today if you ...(13)... New Delhi at 4.00 in the morning, you ...(14)... eat an early breakfast in the sky ...(15)... kabul, and be in London by about 1.00pm. Solve 1